Inbred corn line PHTE4

ABSTRACT

According to the invention, there is provided an inbred corn line, designated PHTE4. This invention thus relates to the plants and seeds of inbred corn line PHTE4 and to methods for producing a corn plant produced by crossing the inbred line PHTE4 with itself or with another corn plant. This invention further relates to hybrid corn seeds and plants produced by crossing the inbred line PHTE4 with another corn line or plant.

This is a continuation of copending application Ser. No. 08/186,730,filed Jan. 24, 1994.

FIELD OF THE INVENTION

This invention is in the field of corn breeding, specifically relatingto an inbred corn line designated PHTE4.

BACKGROUND OF THE INVENTION Plant Breeding

Field crops are bred through techniques that take advantage of theplant's method of pollination. A plant is self-pollinated if pollen fromone flower is transferred to the same or another flower of the sameplant. A plant is cross-pollinated if the pollen comes from a flower ona different plant.

Corn plants (Zea mays L.) can be bred by both self-pollination andcross-pollination techniques. Corn has separate male and female flowerson the same plant, located on the tassel and the ear, respectively.Natural pollination occurs in corn when wind blows pollen from thetassels to the silks that protrude from the tops of the incipient ears.

The development of a hybrid corn variety involves three steps: (1) theselection of plants from various germplasm pools; (2) the selfing of theselected plants for several generations to produce a series of inbredlines, which, although different from each other, breed true and arehighly uniform; and (3) crossing the selected inbred lines withunrelated inbred lines to produce the hybrid progeny (F₁). During theinbreeding process in corn, the vigor of the lines decreases. Vigor isrestored when two unrelated inbred lines are crossed to produce thehybrid progeny. An important consequence of the homozygosity andhomogeneity of the inbred lines is that the hybrid between any twoinbreds will always be the same. Once the inbreds that give a superiorhybrid have been identified, the hybrid seed can be reproducedindefinitely as long as the homogeneity of the inbred parents ismaintained.

The objective of commercial maize inbred line development programs is todevelop new inbred lines that combine to produce high grain yields andsuperior agronomic performance in hybrid combination. The primary traitbreeders seek is yield. However, other major agronomic traits are ofimportance in hybrid combination and have an impact on yield orotherwise provide superior performance in hybrid combinations. Suchtraits include percent grain moisture at harvest, relative maturity,resistance to stalk breakage, resistance to root lodging, grain quality,and disease and insect resistance. In addition the lines per se musthave acceptable performance for parental traits such as seed yields,kernel sizes, pollen production, all of which affect ability to provideparental lines in sufficient quantity and quality for hybridization.Traits have been shown to be under genetic control and many if not allof the traits are affected by multiple genes. Thus, to be selected as aninbred line, the inbred must be able to combine such that the desiredtraits are passed to the hybrid and also be able to satisfy productionrequirements as a parental line.

Pedigree Breeding

The pedigree method of breeding is the mostly widely used methodologyfor new inbred line development.

In general terms this procedure consists of crossing two inbred lines toproduce the non-segregating F₁ generation, and self pollination of theF₁ generation to produce the F₂ generation that segregates for allfactors for which the inbred parents differ. An example of this processis set forth below. Variations of this generalized pedigree method areused, but all these variations produce a segregating generation whichcontains a range of variation for the traits of interest.

EXAMPLE 1 Hypothetical example of pedigree breeding program

Consider a cross between two inbred lines that differ for alleles atfive loci.

The parental genotypes are:

    ______________________________________    Parent 1            A     b     C    d   e   F/A  b   C   d    e   F    Parent 2            a     B     c    D   E   f/a  B   c   D    E   f    ______________________________________

the F₁ from a cross between these two parents is:

    ______________________________________    F.sub.1         A     b      C   d    e   F/a   B   c    D   E    f    ______________________________________

Selfing F₁ will produce an F₂ generation including the followinggenotypes:

    ______________________________________    A    B      c     D       E    f/a  b    C   d    e   F    A    B      c     D       e    f/a  b    C   d    E   F    A    B      c     D       e    f/a  b    C   d    e   F                           .                           .                           .    ______________________________________

The number of genotypes in the F₂ is 3⁶ for six segregating loci (729)and will produce (2⁶)-2 possible new inbreds, (62 for six segregatingloci).

Each inbred parent which is used in breeding crosses represents a uniquecombination of genes, and the combined effects of the genes define theperformance of the inbred and its performance in hybrid combination.There is published evidence (Smith, O. S., J.S.C. Smith, S. L. Bowen, R.A. Tenborg and S. J. Wall, TAG 80:833-840 (1990)) that each of theselines are different and can be uniquely identified on the basis ofgenetically-controlled molecular markers.

It has been shown (Hallauer, Arnel R. and Miranda, J. B. Of.Quantitative Genetics in Maize Breeding, Iowa State University Press,Ames Iowa (1981)) that most traits of economic value in maize are underthe genetic control of multiple genetic loci, and that there are a largenumber of unique combinations of these genes present in elite maizegermplasm. If not, genetic progress using elite inbred lines would nolonger be possible. Studies by Duvick and Russell (Duvick, D. N. Maydica37:69-79 (1992); Russell, W. A. Maydica XXIX:375-390 (1983)) have shownthat over the last 50 years the rate of genetic progress in commercialhybrids has been between 1 and 2% per year.

The number of genes affecting the trait of primary economic importancein maize, grain yield, has been estimated to be in the range of 10-1000.Inbred lines which are used as parents for breeding crosses differ inthe number and combination of these genes. These factors make the plantbreeder's task more difficult. Compounding this is evidence that no oneline contains the favorable allele at all loci, and that differentalleles have different economic values depending on the geneticbackground and field environment in which the hybrid is grown. Fiftyyears of breeding experience shows that there are many genes affectinggrain yield and each of these has a relatively small effect on thistrait. The effects are small compared to breeders' ability to measuregrain yield differences in evaluation trials. Therefore, the parents ofthe breeding cross must differ at several of these loci so that thegenetic differences in the progeny will be large enough that breederscan develop a line that increases the economic worth of its hybrids overthat of hybrids made with either parent.

If the number of loci segregating in a cross between two inbred lines isn, the number of unique genotypes in the F₂ generation is 3^(n) (Example2) and the number of unique inbred lines from this cross is {(2^(n))-2}.Only a very limited number of these combinations are useful. Only about1 in 10,000 of the progeny from F₂ 's are commercially useful.

By way of example, if it is assumed that the number of segregating lociin F₂ is somewhere between 20 and 50, and that each parent is fixed forhalf the favorable alleles, it is then possible to calculate approximateprobabilities of finding an inbred that has the favorable allele at{(n/2)+m} loci, where n/2 is the number of favorable alleles in each ofthe parents and m is the number of additional favorable alleles in thenew inbred. See Example 2 below. The number m is assumed to be greaterthan three because each allele has so small an effect that evaluationtechniques are not sensitive enough to detect differences due to threeor less favorable alleles. The probabilities in Example 2 are on theorder of 10⁻⁵ or smaller and they are the probabilities that at leastone genotype with (n/2)+m favorable alleles will exist.

To put this in perspective the number of plants grown on 60 millionacres (approximate U.S. corn acreage) at 25000 plants/acre is 1.5×10¹².

EXAMPLE 2 Probability of finding an inbred with m of n favorable alleles

Assume each parent has n/2 of the favorable alleles and only 1/2 of thecombinations of loci are economically useful.

    ______________________________________    no. of  no. favorable                        no. additional                                     Probability    segregating            alleles in  favorable alleles                                     that genotype    loci (n)            Parents (n/2)                        in new inbred                                     occurs*    ______________________________________    20      10          14           3 × 10.sup.-5    24      12          16           2 × 10.sup.-5    28      14          18           1 × 10.sup.-5    32      16          20           8 × 10.sup.-6    36      18          22           5 × 10.sup.-6    40      20          24           3 × 10.sup.-6    44      22          26           2 × 10.sup.-6    48      24          28           1 × 10.sup.-6    ______________________________________     *Probability that a useful combination exists, does not include the     probability of identifying this combination if it does exist.

The possibility of having a usably high probability of being able toidentify this genotype based on replicated field testing would be mostlikely smaller than this, and is a function of how large a population ofgenotypes is tested and how testing resources are allocated in thetesting program.

At Pioneer Hi-Bred International, a typical corn research station has astaff of four, and 20 acres of breeding nursery. Those researchers plantthose 20 acres with 25,000 nursery rows, 15,000 yield test plots in10-15 yield test sites, and one or two disease-screening nurseries.Employing a temporary crew of 20 to 30 pollinators, the station makesabout 65,000 hand pollinations per growing season. Thus, one of thelargest plant breeding programs in the world does not have asufficiently large breeding population to be able to rely upon "playingthe numbers" to obtain successful research results. Nevertheless,Pioneer's breeders at each station produce from three to ten new inbredswhich are proposed for commercial use each year. Over the 32 Pioneerresearch stations in North America, this amounts to from about 100 to300 new inbreds proposed for use, and less than 50 and more commonlyless than 30 of these inbreds that actually satisfy the performancecriteria for commercial use.

This is a result of plant breeders using their skills, experience andintuitive ability to select inbreds having the necessary qualities.

SUMMARY OF THE INVENTION

According to the invention, there is provided a novel inbred corn line,designated PHTE4. This invention thus relates to the seeds of inbredcorn line PHTE4, to the plants of inbred corn line PHTE4, and to methodsfor producing a corn plant produced by crossing the inbred line PHTE4with itself or another corn line. This invention further relates tohybrid corn seeds and plants produced by crossing the inbred line PHTE4with another corn line.

DEFINITIONS

In the description and examples that follow, a number of terms are usedherein. In order to provide a clear and consistent understanding of thespecification and claims, including the scope to be given such terms,the following definitions are provided. ABS is in absolute terms and %MN is percent of the mean for the experiments in which the inbred orhybrid was-grown.

BAR PLT=BARREN PLANTS. The percent of plants per plot that were notbarren (lack ears).

BRT STK=BRITTLE STALKS. This is a measure of the stalk breakage near thetime of pollination, and is an indication of whether a hybrid or inbredwould snap or break near the-time of flowering under severe winds. Dataare presented as percentage of plants that did not snap.

BU ACR=YIELD (BUSHELS/ACRE). Actual yield of the grain at harvest inbushels per acre adjusted to 15.5% moisture.

DRP EAR=DROPPED EARS. A measure of the number of dropped ears per plotand represents the percentage of plants that did not drop ears prior toharvest.

EAR HT=EAR HEIGHT. The ear height is a measure from the ground to thehighest placed developed ear node attachment and is measured in inches.

EAR SZ=EAR SIZE. A 1 to 9 visual rating of ear size. The higher therating the larger the ear size.

EST CNT=EARLY STAND COUNT. This is a measure of the stand establishmentin the spring and represents the number of plants that emerge on a perplot basis for the inbred or hybrid.

GDU SHD=GDU TO SHED. The number of growing degree units (GDUs) or heatunits required for an inbred line or hybrid to have approximately 50percent of the plants shedding pollen and is measured from the time ofplanting. Growing degree units are calculated by the Barger Method,where the heat units for a 24-hour period are: ##EQU1##

The highest maximum temperature used is 86° F. and the lowest minimumtemperature used is 50° F. For each inbred or hybrid it takes a certainnumber of GDUs to reach various stages of plant development.

GDU SLK=GDU TO SILK. The number of growing degree units required for aninbred line or hybrid to have approximately 50 percent of the plantswith silk emergence from time of planting. Growing degree units arecalculated by the Barger Method as given in GDU SHD definition.

GRN APP=GRAIN APPEARANCE. This is a 1 to 9 rating for the generalappearance of the shelled grain as it is harvested based on such factorsas the color of the harvested grain, any mold on the grain, and anycracked grain. High scores indicate good grain quality.

MST=HARVEST MOISTURE. The moisture is the actual percentage moisture ofthe grain at harvest.

PLT HT=PLANT HEIGHT. This is a measure of the height of the plant fromthe ground to the tip of the tassel in inches.

POL SC=POLLEN SCORE. A 1 to 9 visual rating indicating the amount ofpollen shed. The higher the score the more pollen shed.

POL WT=POLLEN WEIGHT. This is calculated by dry weight of tasselscollected as shedding commences minus dry weight from similar tasselsharvested after shedding is complete.

It should be understood that the inbred can, through routinemanipulation of cytoplasmic factors, be produced in a cytoplasmicmale-sterile form which is otherwise phenotypically identical to themale-fertile form.

PRM=PREDICTED RM. This trait, predicted relative maturity (RM), is basedon the harvest moisture of the grain. The relative maturity rating isbased on a known set of checks and utilizes standard linear regressionanalyses and is referred to as the Comparative Relative Maturity RatingSystem which is similar to the Minnesota Relative Maturity RatingSystem.

RT LDG=ROOT LODGING. Root lodging is the percentage of plants that donot root lodge; plants that lean from the vertical axis at anapproximately 30° angle or greater would be counted as root lodged.

SCT GRN=SCATTER GRAIN. A 1 to 9 visual rating indicating the amount ofscatter grain (lack of pollination or kernel abortion) on the ear. Thehigher the score the less scatter grain.

SDG VGR=SEEDLING VIGOR. This is the visual rating (1 to 9) of the amountof vegetative growth after emergence at the seedling stage(approximately five leaves). A higher score indicates better vigor.

SEL IND=SELECTION INDEX. The selection index gives a single measure ofthe hybrid's worth based on information for up to five traits. A cornbreeder may utilize his or her own set of traits for the selectionindex. One of the traits that is almost always included is yield. Theselection index data presented in the tables represent the mean valueaveraged across testing stations.

STA GRN=STAY GREEN. Stay green is the measure of plant health near thetime of black layer formation (physiological maturity). A high scoreindicates better late-season plant health.

STK CNT=NUMBER OF PLANTS. This is the final stand or number of plantsper plot.

STK LDG=STALK LODGING. This is the percentage of plants that did notstalk lodge (stalk breakage) as measured by either natural lodging orpushing the stalks and determining the percentage of plants that breakbelow the ear.

TAS BLS=TASSEL BLAST. A 1 to 9 visual rating was used to measure thedegree of blasting (necrosis due to heat stress) of the tassel at timeof flowering. A 1 would indicate a very high level of blasting at timeof flowering, while a 9 would have no tassel blasting.

TAS SZ=TASSEL SIZE. A 1 to 9 visual rating was used to indicate therelative size of the tassel. The higher the rating the larger thetassel.

TAS WT=TASSEL WEIGHT. This is the average weight of a tassel (grams)just prior to pollen shed.

TEX EAR=EAR TEXTURE. A 1 to 9 visual rating was used to indicate therelative hardness (smoothness of crown) of mature grain. A 1 would bevery soft (extreme dent) while a would be very hard (flinty or verysmooth crown).

TILLER=TILLERS. A count of the number of tillers per plot that couldpossibly shed pollen was taken. Data is given as percentage of tillers:number of tillers per plot divided by number of plants per plot,

TST WT=TEST WEIGHT (UNADJUSTED). The measure of the weight of the grainin pounds for a given volume (bushel).

TST WTA=TEST WEIGHT ADJUSTED. The measure of the weight of the grain inpounds for a given volume (bushel) adjusted for percent moisture.

YLD=YIELD. It is the same as BU ACR ABS.

YLD SC=YIELD SCORE. A 1 to 9 visual rating was used to give a relativerating for yield based on plot ear piles. The higher the rating thegreater visual yield appearance.

MDM CPX=Maize Dwarf Mosaic Complex (MDMV=Maize Dwarf Mosaic Virus &MCDV=Maize Chlorotic Dwarf Virus): Visual rating (1-9 score) where a "1"is very susceptible and a "9" is very resistant.

SLF BLT=Southern Leaf Blight (Bipolaris maydis, Helminthosporiummaydis): Visual rating (1-9 score) where a "1" is very susceptible and a"9" is very resistant.

NLF BLT=Northern Leaf Blight (Exserohilum turcicum, H. turcicum): Visualrating (1-9 score) where a "1" is very susceptible and a "9" is veryresistant.

COM RST=Common Rust (Puccinia sorghi): Visual rating (1-9 score) where a"1" is very susceptible and a "9" is very resistant.

GLF SPT=Gray Leaf Spot (Cercospora zeae-maydis): Visual rating (1-9score) where a "1" is very susceptible and a "9" is very resistant.

STW WLT=Stewart's Wilt (Erwinia stewartii): Visual rating (1-9 score)where a "1" is very susceptible and a "9" is very resistant.

HD SMT=Head Smut (Sphacelotheca reiliana): Percentage of plants that didnot have infection.

EAR MLD=General Ear Mold: Visual rating (1-9 score) where a "1" is verysusceptible and a "9" is very resistant. This is based on overall ratingfor ear mold of mature ears without determining specific mold organism,and may not be predictive for a specific ear mold.

ECB DPE=Dropped ears due to European Corn Borer (Ostrinia nubilalis):Percentage of plants that did not drop ears under second brood cornborer infestation.

ECB 2SC=European Corn Borer Second Brood (Ostrinia nubilalis): Visualrating (1-9 score) of post flowering damage due to infestation byEuropean Corn Borer. A "1" is very susceptible and a "9" is veryresistant.

ECB 1LF=European Corn Borer First Brood (Ostrinia nubilalis): Visualrating (1-9 score) of pre-flowering leaf feeding by European Corn Borer.A "1" is very susceptible and a "9" is very resistant.

DETAILED DESCRIPTION OF THE INVENTION

PHTE4 produces hybrids that are high yielding and flower early. PHTE4hybrids have above average seedling vigor, test weight and staygreen.PHTE4 hybrids also have above average resistance to brittle stalks.

Inbred corn line PHTE4 is a yellow, dent corn inbred that provides anacceptable male parental line in crosses for producing first generationF₁ corn hybrids. PHTE4 also provides an acceptable female parental linein crosses for producing first generation F₁ corn hybrids. PHTE4 isadapted to the North Central region of the United States.

The inbred has shown uniformity and stability within the limits ofenvironmental influence for all the traits as described in the VarietyDescription Information (Table 1) that follows. Most of the data in theVariety Description information was collected at Johnston, Iowa. Theinbred has been self-pollinated and ear-rowed a sufficient number ofgenerations with careful attention paid to uniformity of plant type toensure homozygosity and phenotypic stability. The line has beenincreased both by hand and in isolated fields with continued observationfor uniformity. No variant traits have been observed or are expected inPHTE4.

Inbred corn line PHTE4, being substantially homozygous, can bereproduced by planting seeds of the line, growing the resulting cornplants under self-pollinating or sib-pollinating conditions withadequate isolation, and harvesting the resulting seed, using techniquesfamiliar to the agricultural arts.

                  TABLE 1    ______________________________________    VARIETY DESCRIPTION INFORMATION    INBRED = PHTE4    Type: Dent   Region Best Adapted: North Central    ______________________________________    A.  Maturity: Average across maturity zones.        Heat Unit Shed: 1340        Heat Unit Silk: 1330          No. Reps: 35     ##STR1##    *If maximum is greater than 86 degrees fahrenheit, then 86    is used and if minimum is less than 50, then 50 is used.    Heat units accumulated daily and can not be less than 0.    B.  Plant Characteristics:        Plant height (to tassel tip): 207 cm        Length of top ear internode: 10 cm        Number of ears per stalk: Slight, two-ear tendency        Ear height (to base of top ear): 66 cm        Number of tillers: None        Cytoplasm type: Normal    C.  Leaf:        Color: (B14) Dark Green        Angle from Stalk: 30-60 degrees        Marginal Waves: (WF9) Few        Number of Leaves (mature plants): 19        Sheath Pubescebce: (W22) Light        Longitudinal Creases: (PA11) Many        Length (Ear node leaf): 64 cm        Width (widest point, ear node leaf): 7 cm    D.  Tassel:        Number lateral branches: 3        Branch Angle from central spike: >45 degrees        Pollen Shed: Heavy based on Pollen Yield Test        (108% of experiment means)        Peduncle Length (top leaf to basal branches): 21 cm        Anther Color: Purple        Glume Color: Green    E.  Ear (Husked Ear Data Except When Stated Otherwise):        Length: 14 cm        Weight: 127 gm        Mid-point Diameter: 42 mm        Silk Color: Green        Husk Extension (Harvest stage): Long (8-10 cm        beyond ear tip)        Husk Leaf: short (<8 cm)        Taper of Ear: Average        Position of Shank (dry husks): Upright        Kernel Rows: Straight, Distinct Number = 14        Husk Color (fresh): Light Green        Husk Color (dry): Buff        Shank Length: 10 cm        Shank (No. of internodes): 8    F.  Kernel (Dried):        Size (from ear mid-point)        Length: 11 mm        Width: 8 mm        Thick: 4 mm        Shape Grade (% rounds): <20 (18% medium round based        on Parent Test Data)        Pericarp Color: Colorless        Aleurone Color: Homozygous Yellow        Endosperm Color: Yellow        Endosperm Type: Normal Starch        Gm Wt/100 Seeds (unsized): 27 gm    G.  Cob:        Diameter at mid-point: 22 mm        Strength: Strong        Color: Red    H.  Diseases:        Corn Lethal Necrosis (MCMV = Maize Chlorotic Mottle        Virus and MDMV = Maize Dwarf Mosaic        Virus): Resistant        Carbonum Leaf Blight (H. carbonum): Resistant        N. Leaf Blight (E. turcicum): Intermediate        Common Rust (P. sorghi): Resistant        Gray Leaf Spot (C. zeae): Susceptible        Stewart's Wilt (E. stewartii): Resistant        Goss's Wilt (C. Nebraskense): Intermediate        Common Smut (U. maydis): Highly Resistant        Head Smut (S. reiliana): Highly Resistant        Fusarium Ear Mold (F. moniliforme): Intermediate        Gibberella Ear Rot (G. zeae): Intermedaite    I.  Insects:        European Corn Borer-1 Leaf Damage (Pre-flowering):        Resistant        European Corn Borer-2 (Post-flowering): Intermediate        The above descriptions are based on a scale of 1-9, 1 being        highly susceptible, 9 being highly resistant.        S (Susceptible): Would generally represent a score of 1-3.        I (Intermediate): Would generally represent a score of 4-5.        R (Resistant): Would generally represent a score of 6-7.        H (Highly Resistant): Would generally represent a score of        8-9. Highly resistant does not imply the inbred is immune.    J.  Variety Most Closely Resembling:    Character    Inbred    Maturity     PHBW8    Usage        PHBW8    ______________________________________     PHBW8 (PVP Certificate No. 9200079) is a Pioneer HiBred International,     Inc. proprietary inbred.     Data for Items B, C, D, E, F, and G is based primarily on a maximum of tw     reps from Johnston, Iowa grown in 1992, plus description information from     the maintaining station.

ELECTROPHORESIS RESULTS

Isozyme Genotypes for PHTE4

Isozyme data were generated for inbred corn line PHTE4 according to theprocedures described in Stuber, C. W., Wendel, J. F., Goodman, M. M.,and Smith, J. S. C., "Techniques and Scoring Procedures for Starch GelElectrophoresis of Enzymes from Maize (Zea mays L.)", Technical BulletinNo. 286, North Carolina Agricultural Research Service, North CarolinaState University, Raleigh, N.C. (1988).

The data in Table 2 compares PHTE4 with its parents, PHN15 and PHJ40.

                  TABLE 2    ______________________________________    ELECTROPHORESIS RESULTS FOR PHTE4    AND ITS PARENTS PHN15 AND PHJ40                     PARENTS    LOCI     PHTE4         PHN15   PHJ40    ______________________________________    ACP1     2             4       2    ADH1     4             4       4    CAT3     9             9       9    DIA1     8             8       8    GOT1     4             4       4    GOT2     4             4       4    GOT3     4             4       4    IDH1     4             4       4    IDH2     6             6       6    MDH1     6             6       6    MDH2     6             3.5     6    MDH3     16            16      16    MDH4     12            12      12    MDH5     12            12      12    MMM      4             4       4    PGM1     9             9       9    PGM2     4             4       4    PGD1     3.8           2       3.8    PGD2     5             5       5    PHI1     4             4       4    ______________________________________

EXAMPLES INBRED AND HYBRID PERFORMANCE OF PHTE4

In the examples that follow, the traits and characteristics of inbredcorn line PHTE4 are given as a line in comparison with other inbreds andin hybrid combination. The data collected on inbred corn line PHTE4 ispresented for the key characteristics and traits.

Table 3A compares PHTE4 to PHN15. PHTE4has lower yield and grain harvestmoisture but higher test weight compared to PHN15. PHTE4 is a shorterinbred and flowers (GDU Shed and GDU Silk) earlier than PHN15.

The data in Table 3B shows PHTE4 has lower yield and higher grainharvest moisture than PHNV4. PHTE4 and PHNV4 have similar plant heightbut PHTE4 has lower ear placement. PHTE4 is an earlier flowering (GDUShed and GDU Silk) inbred compared to PHNV4.

Table 3C compares PHTE4 to PHJ40. PHTE4 has higher yield and grainharvest moisture but lower test weight compared to PHJ40. PHTE4 has alarger ear and is taller with lower ear placement compared to PHJ40.PHTE4 flowers (GDU Shed and GDU Silk) later than PHJ40. PHTE4 hasgreater pollen weight than PHJ40. PHTE4 has fewer scattergrain, betterstaygreen and better resistance to ear mold and first brood Europeancorn borer than PHJ40.

The data in Table 3D shows PHTE4 has a higher yield than PHT46. PHTE4has a larger ear and is taller with higher ear placement compared toPHT46. PHTE4 flowers (GDU Shed and GDU Silk) later than PHT46. PHTE4 hasa significantly greater pollen weight than PHT46. PHTE4 has better eartexture and staygreen with better resistance to first and second broodEuropean corn borer compared to PHT46.

Table 3E shows PHTE4 has lower yield and grain harvest moisture buthigher test weight compared to PHBW8. PHTE4 and PHBW8 have similar earplacement but PHTE4 is a taller inbred. PHTE4 and PHBW8 shed (GDU Shed)pollen at approximately at the same time but PHTE4 silks (GDU Silk)earlier than PHBW8. PHTE4 has better first brood European corn borerresistance than PHBW8.

Table 4A compares PHTE4 to PHNV4 when both were crossed to the sameinbred testers. The PHTE4 hybrids have higher yield and grain harvestmoisture compared to the PHNV4 hybrids. The PHTE4 hybrids have betterseedling vigor and higher early stand count than the PHNV4 hybrids. ThePHTE4 hybrids are shorter with lower ear placement compared to the PHNV4hybrids.

Table 4B compares PHTE4 to PHRE1 when both were crossed to the sameinbred testers. The hybrids yield similarly but the PHTE4 hybrids havehigher grain harvest moisture than the PHRE1 hybrids. The PHTE4 hybridshave better seedling vigor than the PHRE1 hybrids.

Table 4C compares PHTE4 to PHBW8 when both were crossed to the sameinbred testers. The PHTE4 hybrids have lower yield and grain harvestmoisture compared to the PHBW8 hybrids. The PHTE4 hybrids have bettergrain appearance and seedling vigor than the PHBW8 hybrids.

Table 5A compares PHTE4 to PHBW8 when both were crossed to the sameinbred. The hybrids have similar yield and test weight but the PHTE4hybrid has lower grain harvest moisture. The PHTE4 hybrid is taller withhigher ear placement compared to the PHBW8 hybrid.

Table 5B compares PHTE4 to PHRE1 when both were crossed to the sameinbred. The hybrids yield similarly but the PHTE4 hybrid hassignificantly higher grain harvest moisture than the PHRE1 hybrid. ThePHTE4 hybrid has better test weight than the PHRE1 hybrid. The hybridsare similar in height but the PHTE4 hybrid has lower ear placement.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 compares the yield of PHTE4 and PHJ40. PHTE4 is higher yieldingacross all environments compared to PHJ40. PHTE4 has above average yieldin low yield environments but below average yield in high yieldenvironments whereas PHJ40 has below average yield over allenvironments.

FIG. 2 compares the yield of PHTE4 and PHBW8. PHTE4 is lower yieldingthan PHBW8 but the differential is less in low yield environments.

                                      TABLE 3C    __________________________________________________________________________    PAIRED INBRED COMPARISON DATA    __________________________________________________________________________                 BU  BU  YLD     EAR BAR PLT EAR SDG  EST TIL  GDU            VAR  ACR ACR SC  MST SZ  PLT HT  HT  VGR  CNT LER  SHD    DEPT    #    ABS % MN                         ABS ABS ABS ABS ABS ABS ABS  ABS ABS  ABS    __________________________________________________________________________    TOTAL SUM            1    91.0                     100 5.0 21.9                                 4.0 98.0                                         81.3                                             28.5                                                 7.2  54.3                                                          1.3  1280            2    110.1                     122 5.0 23.9                                 6.0 99.5                                         88.2                                             28.5                                                 6.8  55.2                                                          0.3  1343            LOCS 3   3   1   3   1   5   3   3   5    3   4    3            REPS 6   6   1   6   1   8   5   5   8    6   7    4            DIFF 19.1                     21  0.0 2.0 2.0 1.5 6.8 0.0 0.4  0.8 1.0  63            PROB .005+                     .013+   .026+   .241                                         .059*                                             .000#                                                 .405 .338                                                          .525 .019+    __________________________________________________________________________                                   GDU POL TAS TST SCT STA STK ECB                              VAR  SLK SC  SZ  WT  GRN GRN LDG 1LF                      DEPT    #    ABS ABS ABS ABS ABS ABS ABS ABS    __________________________________________________________________________                      TOTAL SUM                              1    1295                                       5.0 4.0 60.1                                                   7.0 4.7 90.5                                                               7.0                              2    1360                                       5.0 3.0 57.3                                                   7.0 5.7 81.8                                                               6.0                              LOCS 2   1   2   3   1   3   4   1                              REPS 2   1   2   6   1   6   7   1                              DIFF 65  0.0 1.0 2.8 0.0 1.0 8.7 1.0                              PROB .144    .500                                               .075*   .074*                                                           .408    __________________________________________________________________________     VARIETY #1  PHTE4     VARIETY #2  PHN15     * = 10% SIG     + = 5% SIG     # = 1% SIG

                                      TABLE 3D    __________________________________________________________________________    PAIRED INBRED COMPARISON DATA    __________________________________________________________________________              BU  BU  YLD     EAR BAR PLT EAR SDG EST TIL GDU  GDU         VAR  ACR ACR SC  MST SZ  PLT HT  HT  VGR CNT LER SHD  SLK    DEPT #    ABS % MN                      ABS ABS ABS ABS ABS ABS ABS ABS ABS ABS  ABS    __________________________________________________________________________    TOTAL         1    76.7                  100 6.0 32.7                              5.0 94.6                                      78.3                                          30.5                                              5.9 33.6                                                      4.3 1203 1198    SUM  2    97.5                  126 6.0 27.5                              5.0 93.3                                      80.3                                          35.3                                              7.0 31.7                                                      1.4 1224 1239         LOCS 1   1   2   2   1   3   6   6   7   12  6   10   10         REPS 2   2   2   4   1   3   6   6   7   14  6   10   10         DIFF 20.7                  27  0.0 5.2 0.0 1.3 2.0 4.8 1.1 1.9 3.0 21   41         PROB         1.00                          .169    .855                                      .710                                          .048+                                              .084*                                                  .258                                                      .566                                                          .035+                                                               .005#    __________________________________________________________________________                POL TAS TAS TEX TST GRN SCT STA EAR  NLF  ECB  ECB            VAR SC  BLS SZ  EAR WT  APP GRN GRN MLD  BLT  1LF  2SC    DEPT    #   ABS ABS ABS ABS ABS ABS ABS ABS ABS  ABS  ABS    __________________________________________________________________________    TOTAL SUM            1   4.5 9.0 4.5 7.0 52.7                                    7.0 9.0 6.0 9.0  8.0  7.0  3.0            2   5.5 9.0 4.8 7.0 52.8                                    6.0 7.5 5.0 9.0  7.0  7.0  6.0            LOCS                2   1   4   1   1   1   2   3   1    1    3    1            REPS                2   1   4   1   2   1   2   3   1    1    3    1            DIFF                1.0 0.0 0.3 0.0 0.2 1.0 1.5 1.0 0.0  1.0  0.0  3.0            PROB    .718            .205                                        .580         .000#    __________________________________________________________________________     VARIETY #1  PHTE4     VARIETY #2  PHNV4     * = 10% SIG     + = 5% SIG     # = 1% SIG

                                      TABLE 3C    __________________________________________________________________________    PAIRED INBRED COMPARISON DATA    __________________________________________________________________________                 BU  BU  YLD     EAR BAR PLT EAR SDG EST  DRP  TIL            VAR  ACR ACR SC  MST SZ  PLT HT  HT  VGR CNT  EAR  LER    DEPT    #    ABS % MN                         ABS ABS ABS ABS ABS ABS ABS ABS  ABS  ABS    __________________________________________________________________________    TOTAL SUM            1    77.2                     99  6.1 23.2                                 6.2 96.8                                         77.9                                             29.2                                                 5.9 42.3 99.6 2.7            2    64.2                     83  5.3 17.4                                 4.8 94.5                                         63.4                                             27.2                                                 5.8 41.4 99.7 1.1            LOCS 17  17  7   21  5   28  24  24  25  57   6    37            REPS 48  48  7   53  5   41  42  42  41  115  14   67            DIFF 13.1                     16  0.9 5.8 1.4 2.3 14.6                                             2.0 0.1 0.9  0.1  1.6            PROB .001#                     .002#                         .172                             .000#                                 .005#                                     .131                                         .000#                                             .030+                                                 .719                                                     .150 .760 .249    __________________________________________________________________________                 GDU GDU POL POL POL TAS TAS TEX TST GRN  SCT  STA            VAR  SHD SLK WT  WT  SC  BLS SZ  EAR WT  APP  GRN  GRN    DEPT    #    ABS ABS ABS % MN                                 ABS ABS ABS ABS ABS ABS  ABS  ABS    __________________________________________________________________________    TOTAL SUM            1    1277                     1275                         131.0                             104 5.3 9.0 4.7 7.0 57.9                                                     6.3  8.2  5.7            2    1175                     1185                         111.3                             86  4.9 9.0 4.5 7.5 59.4                                                     6.1  6.8  2.2            LOCS 41  37  9   9   20  5   10 2                                             17  9   6    12            REPS 59  49  18  18  32  9   10  2   47  19   6    21            DIFF 102 90  19.7                             18  0.3 0.0 0.2 0.5 1.4 0.1  1.3  3.4            PROB .000#                     .000#                         .041+                             .052*                                 .235                                     1.00                                         .662                                             .500                                                 .002#                                                     .844 .001#                                                               .000#    __________________________________________________________________________                                           STK RT  EAR NLF ECB ECB                                      VAR  LDG LDG MLD BLT 1LF 2SC                              DEPT    #    ABS ABS ABS ABS ABS ABS    __________________________________________________________________________                              TOTAL SUM                                      1    97.3                                               98.9                                                   7.4 5.4 6.2 4.2                                      2    97.3                                               98.2                                                   6.0 4.5 3.4 3.8                                      LOCS 11  5   5   6   9   5                                      REPS 27  12  5   7   9   6                              DIFF    0.0  0.7 1.4 0.9 2.8 0.4                                      PROB .992                                               .516                                                   .005#                                                       .403                                                           .001#                                                               .688    __________________________________________________________________________     VARIETY #1  PHTE4     VARIETY #2  PHJ40     * = 10% SIG     + = 5% SIG     # = 1% SIG

                                      TABLE 3D    __________________________________________________________________________    PAIRED INBRED COMPARISON DATA    __________________________________________________________________________                 YLD     EAR BAR PLT EAR SDG EST TIL GDU GDU  POL            VAR  SC  MST SZ  PLT HT  HT  VGR CNT LER SHD SLK  WT    DEPT    #    ABS ABS ABS ABS ABS ABS ABS ABS ABS ABS ABS  ABS    __________________________________________________________________________    TOTAL SUM            1    6.3 12.8                         6.2 95.6                                 78.8                                     31.4                                         5.6 29.9                                                 2.2 1268                                                         1268 131.7            2    5.0 12.0                         5.2 90.6                                 62.3                                     25.5                                         5.6 28.7                                                 2.3 1168                                                         1167 83.1            LOCS 8   2   5   16  11  11  17  35  20  29  29   4            REPS 8   2   5   16  11  11  17  60  24  33  33   8            DIFF 1.3 0.8 1.0 5.0 16.5                                     5.8 0.1 1.1 0.1 100 101  48.7            PROB .011+                     .500                         .034+                             .228                                 .000#                                     .049+                                         .884                                             .114                                                 .949                                                     .000#                                                         .000#                                                              .055*    __________________________________________________________________________                 POL POL TAS TAS TEX GRN SCT STA EAR NLF ECB  ECB            VAR  WT  SC  BLS SZ  EAR APP GRN GRN MLD BLT 1LF  2SC    DEPT    #    % MN                     ABS ABS ABS ABS ABS ABS ABS ABS ABS ABS  ABS    __________________________________________________________________________    TOTAL SUM            1    115 5.3 9.0 4.6 7.0 7.0 8.3                                         5.0 7.4                                             5.2 6.3 4.3            2    71  4.8 9.0 4.4 6.0 5.0 7.6 2.5 6.6 5.6 4.1  3.0            LOCS 4   12  3   11  2   1   7   4   5   5   9    3            REPS 8   16  5   11  2   1   7   4   5   5   9    3            DIFF 45  0.5 0.0 0.3 1.0 2.0 0.7 2.5 0.8 0.4 2.2  1.3            PROB .052*                     .237                         1.00                             .625                                 .000#   .220                                             .030+                                                 .242                                                     .688                                                         .013+                                                              .057*    __________________________________________________________________________     VARIETY #1  PHTE4     VARIETY #2  PHJ40     * = 10% SIG     + = 5% SIG     # = 1% SIG

                                      TABLE 3E    __________________________________________________________________________    PAIRED INBRED COMAPRISON DATA    __________________________________________________________________________                 BU  BU  YLD     EAR BAR PLT EAR SDG EST DRP  TIL            VAR  ACR SC  MST SZ  PLT HT  HT  VGR CNT EAR LER    DEPT    #    ABS % MN                         ABS ABS ABS ABS ABS ABS ABS ABS ABS  ABS    __________________________________________________________________________    TOTAL SUM            1    80.4                     97  6.1 20.9                                 5.2 97.0                                         76.3                                             29.5                                                 5.9 39.0                                                         99.7 2.9            2    92.0                     111 6.4 22.0                                 6.4 97.4                                         72.6                                             29.5                                                 5.9 39.5                                                         100.0                                                              1.9            LOCS 16  16  10  22  10  25  31  31  34  61  7    39            REPS 34  34  10  41  10  31  46  46  40  106 16   58            DIFF 11.6                     14  0.3 1.1 1.2 0.4 3.7 0.0 0.0 0.6 0.3  0.9            PROB .000#                     .000#                         .541                             .008#                                 .005#                                     .642                                         .002#                                             978 .911                                                     .341                                                         .172 .479    __________________________________________________________________________                 GDU DGU POL POL POL TAS TAS TEX TST GRN SCT  STA            VAR  SGD SLK WT  WT  SC  BLS SZ  EAR WT  APP GRN  GRN    DEPT    #    ABS ABS ABS % MN                                 ABS ABS ABS ABS ABS ABS ABS  ABS    __________________________________________________________________________    TOTAL SUM            1    1276                     1274                         134.8                             100 5.1 9.0 4.6 6.3 58.3                                                     6.8 7.5  5.2            2    1278                     1292                         108.4                             78  4.2 9.0 4.1 6.5 55.7                                                     5.6 7.1  5.1            LOCS 44  42  6   6   18  3   14  6   14  7   12   14            REPS 56  52  12  12  27  5   16  6   30  15  12   20            DIFF 02  18  26.5                             22  0.9 0.0 0.5 0.2 2.5 1.3 0.4  0.1            PROB .604                     .003#                         .180                             .145                                 .005#                                     1.00                                         .197                                             .771                                                 .000#                                                     .139                                                         .499 .720    __________________________________________________________________________                                       STK RT  EAR NLF STW ECB ECB                                  VAR  LDG LDG MLD BLT WLT 1LF 2SC                          DEPT    #    ABS ABS ABS ABS ABS ABS ABS    __________________________________________________________________________                          TOTAL SUM                                  1    92.1                                           99.2                                               7.9 5.2 7.0 6.4 4.2                                  2    92.1                                           94.7                                               7.9 5.8 7.0 4.3 4.8                                  LOCS 12  7   10  9   1   15  5                                  REPS 25  15  10  12  1   18  6                                  DIFF 0.0 4.5 0.0 0.6 0.0 2.1 0.6                                  PROB .999                                           .244                                               .000#                                                   .155    .000#                                                               .426    __________________________________________________________________________     * = 10% SIG     + = 5% SIG     # = 1% SIG     VARIETY #1  PHTE4     VARIETY #2  PHBW8     * = 10% SIG     + = 5% SIG     # = 1% SIG

                                      TABLE 4A    __________________________________________________________________________    AVERAGE INBRED BY TESTER PERFORMANCE COMPARING PHNV4 TO PHTE4 CROSSED TO    THE SAME INBRED    TESTERS AND GROWN IN THE SAME EXPERIMENTS. ALL VALUES ARE EXPRESSED AS    PERCENT OF THE    EXPERIMENT MEAN EXCEPT PREDICTED RM, SELECTION INDEX, AND YIELD    __________________________________________________________________________    (BU/ACR).                      SEL BU          GDU PRM STK RT  STA TST GRN           KINBR1ED                  PRM IND ACR YLD MST SHD SHD LDG LDG GRN WTA APP    __________________________________________________________________________    TOTAL  REPLIC.                  20  20  20  20  20  6   2   14  7   4   20  8    MEAN WTS           PHNV4  101 106 154 104 105 99  98  101 99  98  99  99    MEAN WTS           PHTE4  101 117 166 111 106 100 99  100 96  89  100 101           DIFF.      11  12  7   0   1   1   0   3   9   1   2    __________________________________________________________________________                                       SDG EST STK PLT EAR DRP BRT                                KINDRED                                       VGR CNT CNT HT  HT  EAR STK    __________________________________________________________________________                         TOTAL  REPLIC.                                       9   14  20  9   9   4   2                         MEAN WTS                                PHNV4  108 95  97  104 108 100 100                         MEAN WTS                                PHTE4  113 103 103 98  95  100 99                                DIFF.  4   8   6   5   13      1    __________________________________________________________________________

                                      TABLE 4B    __________________________________________________________________________    AVERAGE INBRED BY TESTER PERFORMANCE COMPARING PHRE1 TO PHTE4 CROSSED TO    THE SAME INBRED    TESTERS AND GROWN IN THE SAME EXPERIMENTS. ALL VALUES ARE EXPRESSED AS    PERCENT OF THE    EXPERIMENT MEAN EXCEPT PREDICTED RM, SELECTION INDEX, AND YIELD    __________________________________________________________________________    (BU/ACR).                      SEL BU          GDU PRM STK RT  STA TST GRN           KINBRED                  PRM IND ACR YLD MST SHD SHD LDG LDG GRN WTA APP    __________________________________________________________________________    TOTAL  REPLIC.                  12  12  12  12  12  3   1   8   12  6   8   12    MEAN WTS           PHRE1  99  123 170 115 99  99  98  101 98  95  106 106    MEAN WTS           PHTE4  101 119 168 113 109 101 100 101 100 117 104 103           DIFF.  2   4   2   2   10  1   1   0   2   22  3   3    __________________________________________________________________________                                                PLT  EAR  DRP  BRT                                        KINDRED HT   HT   EAR  STK    __________________________________________________________________________                                 TOTAL  REPLIC. 4    4    4    2                                 MEAN WTS                                        PHRE1   100  111  100  100                                 MEAN WTS                                        PHTE4   99   94   100  99                                        DIFF.   1    17        1    __________________________________________________________________________

                                      TABLE 4C    __________________________________________________________________________    AVERAGE INBRED BY TESTER PERFORMANCE COMPARING PHTE4 TO PHBW8 CROSSED TO    THE SAME INBRED    TESTERS AND GROWN IN THE SAME EXPERIMENTS. ALL VALUES ARE EXPRESSED AS    PERCENT OF THE    EXPERIMENT MEAN EXCEPT PREDICTED RM, SELECTION INDEX, AND YIELD    __________________________________________________________________________    (BU/ACR).                      SEL BU          GDU PRM STK RT  STA TST GRN           KINBRED                  PRM IND ACR YLD MST SHD SHD LDG LDG GRN WTA APP    __________________________________________________________________________    TOTAL  REPLIC.                  166 176 181 181 182 60  15  151 83  71  170 122    MEAN WTS           PHTE4  104 101 161 100 99  98  102 98  101 94  102 108    MEAN WTS           PHBW8  106 102 165 102 104 100 102 103 101 115 101 97           DIFF.  2   1   4   2   5   1   0   4   0   21  1   12    __________________________________________________________________________                                       SDG EST STK PLT EAR DRP BRT                                KINDRED                                       VGR CNT CNT HT  HT  EAR STK    __________________________________________________________________________                         TOTAL  REPLIC.                                       72  149 217 99  99  76  4                         MEAN WTS                                PHTE4  108 102 101 99  96  100 101                         MEAN WTS                                PHBW8  106 102 100 95  95  100 101                                DIFF.  3   0   1   4   1   0   1    __________________________________________________________________________

                                      TABLE 5A    __________________________________________________________________________                                   BU  BU      STK RT  STA TST GRN            VAR      PRM           ACR ACR MST LDG LDG GRN WTA APP    DEPT    #    PRM SHD           ABS % MN                                           % MN                                               % MN                                                   % MN                                                       % MN                                                           %                                                               %    __________________________________________________________________________                                                               MN    TOTAL SUM            1    105 102           162.9                                       105 102 103 101 97  101 104            2    106 101           163.4                                       104 105 104 102 105 101 104            LOCS 13  7             47  47  47  39  22  16  45  25            REPS 13  7             63  63  63  52  30  19  61  36            DIFF 1   1             0.5 0   3   1   1   8   0   0            PROB.                 .005#                     .357          .868                                       .830                                           .003#                                               .192                                                   .670                                                       .216                                                           .298                                                               .964    __________________________________________________________________________                                   SDG EST STK PLT EAR DRP BRT GDU                           VAR     VGR CNT CNT HT  HT  EAR STK SHD                  DEPT             #   % MN                                           % MN                                               % MN                                                   % MN                                                       % MN                                                           %                                                               % MN                  TOTAL SUM                           1       110 103 100 99  191 100 101 99                           2       112 102 100 93  95  100 99  99                           LOCS    22  27  53  18  18  23  1   15                           REPS    31  32  71  21  21  31  1   19                           DIFF2   1   0   6   6   0   2   1                           PROB    .578                                       .506                                           .643                                               000#                                                   .011+                                                       .328    .278    __________________________________________________________________________     VARIETY #1  PHTE4 HYBRID     VARIETY #2  PHBW8 HYBRID     * = 10% SIG     + = 5% SIG     # = 1% SIG

                                      TABLE 5B    __________________________________________________________________________                      BU  BU      STK TST SDG EST STK PLT EAR GDU         VAR      PRM ACR ACR MST LDG WTA VGR CNT CNT HT  HT  SHD    DEPT #    PRM SHD ABS % MN                              % MN                                  % MN                                      % MN                                          % MN                                              % MN                                                  % MN                                                      % MN                                                          %                                                              %    __________________________________________________________________________                                                              MN    TOTAL         1    101 99  167.7                          113 108 101 100 116 104 103 99  94  101    SUM  2    99  98  170.4                          115 99  101 98  95  107 106 100 111 99         LOCS 1   1   6   6   6   4   6   3   4   5   2   2   2    REPS 1    1   12  12  12  8   12  6   8   12  4   4   3    DIFF 2    1   2.7 2   10  0   2   21  3   3   1   17  2    PROB          .635                      .587                          .004#                              .391                                  .078*                                      .195                                          .532                                              .532                                                  .500                                                      .219                                                          .392    __________________________________________________________________________     VARIETY #1  PHTE4 HYBRID     VARIETY #2  PHRE1 HYBRID     * = 10% SIG     + = 5% SIG     # = 1% SIG

INDUSTRIAL APPLICABILITY

The foregoing is set forth by way of example and is not intended tolimit the scope of the invention.

This invention also is directed to methods for producing a corn plant bycrossing a first parent corn plant with a second parent corn plantwherein the first or second parent corn plant is an inbred corn plantfrom the line PHTE4. Further, both first and second parent corn plantscan come from the inbred corn line PHTE4. Thus, any such methods usingthe inbred corn line PHTE4 are part of this invention: selfing,backcrosses, hybrid production, crosses to populations, and the like. Italso would include more unconventional methods of combining the inbredwith another such as using various culturing techniques known to thoseskilled in the art. All plants produced using inbred corn line PHTE4 asa parent are within the scope of this invention. Advantageously, theinbred corn line is used in crosses with other, different, corn inbredsto produce first generation (F₁) corn hybrid seeds and plants withsuperior characteristics.

Corn plants (Zea mays L.) can be bred by both self-pollination andcross-pollination techniques. Corn has male flowers, located on thetassel, and female flowers, located on the ear, on the same plant.Natural pollination occurs in corn when wind blows pollen from thetassels to the silks that protrude from the tops of the incipient ears.Backcrossing can be used to transfer monogenic traits from on line toanother. This can be accomplished for example by first crossing asuperior inbred (A) (recurrent parent) to a donor inbred (non-recurrentparent), which carries the appropriate gene(s) for the trait inquestion. The progeny of this cross is then mated back to the superiorrecurrent parent (A) followed by selection in the resultant progeny forthe desired trait to be transferred from the non-recurrent parent. Afterfive or more backcross generations with selection for the desired trait,the progeny will be heterozygous for loci controlling the characteristicbeing transferred, but will be like the superior parent for most oralmost all other genes. The last backcross generation would be selfed togive pure breeding progeny for the gene(s) being transferred.

Hybrid corn seed is produced by planting male and female parental linesin sufficient proximity to permit pollination of the female line by themale line ("pollinating proximity"). To assure genetic uniformity andavoid self-pollination, steps are taken to prevent pollen formation bythe plants of the parental line chosen to serve as the female. This ismost commonly done by manual detasseling. Alternate strips of theparental lines of corn are planted in a field, and the pollen-bearingtassels are physically removed from the female plants, either by hand orby machine. Providing that there is sufficient isolation from othersources of corn pollen, the ears of the female plants will be fertilizedonly from pollen from the male plants, and the resulting seed istherefore hybrid and will form hybrid plants. In a single-cross hybrid,both parents are inbred lines. In a double-cross hybrid, both parentsare the F₁ offspring of a cross of two inbred lines. In a three-waycross, one of the parents is an inbred line and the other parent is anF₁ hybrid. Each cross is made in the manner described herein.

Unfortunately, the manual detasseling process is not entirely reliable.Occasionally a female plant will be blown over by a storm and escapedetasseling. Or, a detasseler will not completely remove the tassel ofthe plant. In either event, the female plant will successfully shedpollen and some female plants will be self-pollinated. This will resultin seed of the female inbred being harvested along with the hybrid seedwhich is normally produced.

Alternatively, the female inbred can be mechanically detasseled.Mechanical detasseling is approximately as reliable as manualdetasseling, but is faster and less costly. However, most detasselingmachines produce more damage to the plants than manual detasseling.

The laborious detasseling process can be avoided by using cytoplasmicmale-sterile (CMS) inbreds. Plants of a CMS inbred are male sterile (donot form pollen) as a result of cytoplasmic factors resulting from thecytoplasmic, as distinguished from the nuclear, genome. Thus, thischaracteristic is inherited exclusively through the female parent, sincethe female parent provides the cytoplasm of the fertilized seed. CMSplants are fertilized with pollen from another inbred that is notmale-sterile. Pollen from the male parent may or may not contributegenes that make the hybrid plants male-fertile. Usually seed fromdetasseled normal maize and CMS-produced seed of the same hybrid must beblended to insure that adequate pollen loads are available forfertilization when the hybrid plants are grown.

There can be other drawbacks to CMS. One is an historically observedassociation of a specific variant of CMS with susceptibility to certaincrop diseases. This problem has led to widespread abandonment of use ofthat CMS variant in producing hybrid maize. In addition, CMS sometimeshas a negative association with agronomic performance, particularly inthe areas of stalk quality, early seedling vigor, and yield. Finally,CMS exhibits on occasion the potential for breakdown of sterility incertain environments, rendering CMS lines unreliable for hybrid seedproduction.

Another form of sterility, genic male sterility, is disclosed in U.S.Pat. Nos. 4,654,465 and 4,727,219 to Brar et al. However, this form ofgenetic male Sterility requires maintenance of multiple mutant genes atseparate locations within the genome and requires a complex markersystem to track the genes and make use of the system convenient. Anotherform of male sterility is imparted in a manner by which expression of atransgene produces a "pollen-toxic" compound which blocks pollenformation in some manner.

Still another form of genetic male sterility uses an inducible promoterto regulate expression of a gene which is known to be critical inmicrosporogenesis, i.e., the production of pollen. The selected gene iscloned, its native promoter removed, and the modified gene is insertedinto an expression sequence with an inducible promoter responsive toexternal control. Preferably, the promoter is one which responds toapplication of a specific non-phytotoxic chemical to the plant. Usingtransformation and gene substitution, the "critical" gene is deletedfrom the genome of the plant and replaced by the genetically-engineeredgene incorporated into the expression sequence with the induciblepromoter. In this method, the inducible promoter is used to inducefertility, not sterility. The selected gene's promoter sequences areremoved so that the gene is not transcribed and the plant is malesterile. When it is desired to increase the male-sterile plant, malefertility is restored by inducing expression of the critical gene with aspecific non-phytotoxic chemical. Any of the foregoing methods andcombinations thereof can be used to prevent pollen formation by thefemale parent of the hybrid. As used herein, the term plant includesplant cells, plant protoplasts, plant cell tissue cultures from whichcorn plants can be regenerated, plant calli, plant clumps, and plantcells that are intact in plants or parts of plants, such as embryos,pollen, flowers, kernels, ears, cobs, leaves, husks, stalks, roots, roottips, anthers, silk and the like.

Duncan, Williams, Zehr, and Widholm, Planta, (1985) 165:322-332 reflectsthat 97% of the plants cultured which produced callus were capable ofplant regeneration. Subsequent experiments with both inbreds and hybridsproduced 91% regenerable callus which produced plants. In a furtherstudy in 1988, Songstad, Duncan & Widholm in Plant Cell Reports (1988),7:262-265 reports several media additions which enhance regenerabilityof callus of two inbred lines. Other published reports also indicatedthat "nontraditional" tissues are capable of producing somaticembryogenesis and plant regeneration. K. P. Rao, et al., Maize GeneticsCooperation Newsletter, 60:64-65 (1986), refers to somatic embryogenesisfrom glume callus cultures and B. V. Conger, et al., Plant Cell Reports,6:345-347 (1987) indicates somatic embryogenesis from the tissuecultures of maize leaf segments. Thus, it is clear from the literaturethat the state of the art is such that these methods of obtaining plantsare "conventional" in the sense that they are routinely used and have avery high rate of success. It should also be clear that the term"regenerable cells" as used in the claims should be construed broadly toinclude any of the foregoing examples of regenerable cells, when theyhave the genotype of PHTE4.

Tissue culture of corn is described in European Patent Application,publication 160,390, incorporated herein by reference. Corn tissueculture procedures are also described in Green and Rhodes, "PlantRegeneration in Tissue Culture of Maize," Maize for Biological Research(Plant Molecular Biology Association, Charlottesville, Va. 1982, at367-372) and in Duncan, et al., "The Production of Callus Capable ofPlant Regeneration from Immature Embryos of Numerous Zea MaysGenotypes," 165 Planta 322-332 (1985). Thus, another aspect of thisinvention is to provide cells which upon growth and differentiationproduce corn plants having the genotype of the inbred line PHTE4. Suchplants, after self-pollination, will yield plants having thephysiological and morphological characteristics of PHTE4.

Corn is used as human food, livestock feed, and as raw material inindustry. The food uses of corn, in addition to human consumption ofcorn kernels, include both products of dry- and wet-milling industries.The principal products of corn dry milling are grits, meal and flour.The corn wet-milling industry can provide corn starch, corn syrups, anddextrose for food use. Corn oil is recovered from corn germ, which is aby-product of both dry- and wet-milling industries.

Corn, including both grain and non-grain portions of the plant, is alsoused extensively as livestock feed, primarily for beef cattle, dairycattle, hogs, and poultry.

Industrial uses of corn are mainly from corn starch in the wet-millingindustry and corn flour in the dry-milling industry. The industrialapplications of corn starch and flour are based on functionalproperties, such as viscosity, film formation, adhesive properties, andability to suspend particles. The corn starch and flour have applicationin the paper and textile industries. Other industrial uses includeapplications in adhesives, building materials, foundry binders, laundrystarches, explosives, oil-well muds, and other mining applications.

Plant parts other than the grain of corn are also used in industry.Stalks and husks are made into paper and wallboard and cobs are used forfuel and to make charcoal.

The seed of inbred corn line PHTE4, the plant produced from the inbredseed, the hybrid corn plant produced from the crossing of the inbred,hybrid seed, and various parts of the hybrid corn plant can be utilizedfor human food, livestock feed, and as a raw material in industry.

Although the foregoing invention has been described in some detail byway of illustration and example for the purposes of clarity andunderstanding, it will be obvious that certain changes and modificationsmay be practiced within the scope of the invention, as limited only bythe scope of the appended claims.

DEPOSIT STATEMENT

Applicant has made a deposit of at least 2500 seeds of Inbred Corn LinePHTE4 with the American Type Culture Collection (ATCC), Rockville, Md.20852 USA, ATCC Deposit No. 97065. The seeds deposited with the ATCC onFeb. 22, 1995 were taken from the deposit manufactured by PioneerHi-Bred International, Inc., 700 Capital Square, 400 Locust Street, DesMoines, Iowa 50309-2340 since prior to the filing date of thisapplication. This deposit of the Inbred Corn Line PHTE4 will bemaintained in the ATCC depository, which is a public depository, for aperiod of 30 years, or 5 years after the most recent request, or for theenforceable life of the patent, whichever is longer, and will bereplaced if it becomes nonviable during that period. Additionally,Applicant has satisfied all the requirements of 37 C.F.R. §§1.801-1.809,including providing an indication of the viability of the sample.Applicant imposes no restrictions on the availability of the depositedmaterial from the ATCC; however, Applicant has no authority to waive anyrestrictions improsed by law on the transfer of biological material orits transportation in commerce. Applicant does not waive anyinfringement of its rights granted under this patent or under the PlantVariety Protection Act (7 USC 2321 et seq.). PHTE4 is a U.S. ProtectedVariety under Plant Variety Protection Certificate No. 9400094.

What is claimed is:
 1. A process of producing a novel corn seed havingallales which, when expressed, contribute to high yield, good resistanceto stalk breakage which compared to other hybrids adapted to, theNorthcentral Region of the Untied States, and superior plant height inrelation to stalk characteristics, comprising the steps of:(a) planting,in pollinating proximity, seeds of two parental lines, one of theparental lines being PHTE4 having ATCC Accession No. 97065, and theother parental line having a genotype different from PHTE4; (b)cultivating corn plants resulting from said planting; (c) preventingpollen formation by the plants of one of the parental lines; (d)allowing natural cross pollinating to occur between said parental lines;and (e) harvesting seeds produced by the plants which do not formpollen.